Propagating conformational changes over long (and short) distances in proteins

The problem of the propagation of conformational changes over long distance s or through a closely packed protein is shown to fit a model of a ligand-i nduced conformational change between two protein states selected by evoluti on. Moreover, the kinetics of the pathway between these states is also sele cted so that the energy of ligand binding and the speed of the transition b etween conformational states are physiologically appropriate. The crystallo graphic data of a wild-type aspartate receptor that has negative cooperativ ity and a mutant that has no cooperativity but has native transmembrane sig naling are shown to support this model.